Toroidal heat exchangers



y 1962 R. F. CAUGHILL ETAL 3,033,534

TOROIDAL HEAT EXCHANGERS 3 Sheets-Sheet 1 Filed Jan. 29, 1959 INVENTOR-S/?fllzzt jeqyrf cf BY za/ilyaaizzzye'z ATTUFIVEY y 1962 R. F. CAUGHILLETAL 3,033,534

TOROIDAL HEAT EXCHANGERS 3 Sheets-Sheet 2 Filed Jan. .29, 1959 May 8,1962 R. F. CAUGHILL ET'AL 3,033,534

TOROIDAL HEAT EXCHANGERS 3 Sheets-Sheet 5 Filed Jan. 29, 1959 UnitedStates Patent 3,033,534 TDRQIDAL HEAT EXCHANGERS Robert F. Canghill andFrank A. Disinger,.Lockport,

N.Y., assignors to General Motors Corporation, Detroit, Mich, acorporation of Delaware Filed Jan. 29, 1959, Ser. No. 790,016 3 Claims.(Cl. 257--235) fatigue and rupture. Total pressure drop of fluidspassing through the exchangers should be minimized in the interest ofupholding exchanger efliciency at the same time thatexpansion-contraction problems should be solved.

To these ends, an object of the present invention is to Patented May 8,1962 "ice tube 14 and the passages 16 are such that a fluid entering at18 will pass substantially the full length of the tube 14 provide animproved heat exchanger characterized by a minimum prmsure drop offluids utilized and by a structure in which expansion and contraction ofthe parts are permitted without incurring undue stresses and strains.

A- feature of the invention pertains to a toroidal heat exchangerutilizing involute tubes arranged in groups or sections. Another featurepertains to a heat exchanger with involute tubes in plate form and ofsubstantially equal lengths alternating with air centering devices aboutan axis in such a way as to provide uniform air flow through across-section ofthe exchanger as well. as uniform fluid flow through allthe tube lengths.

The above and other features of the invention willnow bedescribed indetail in the specification and then pointed out more particularly inthe appended claims.

In the drawings:

FIG. 1 is a perspective view of a heat exchanger in 'which the presentinvention is embodied, portions being shown in FIG. 1 and drawn to anenlarged scale;

FIG. 4 is a view of a detail in the structure of the assembly of FIG. 1,it being drawn to a still larger scale; and

FIG. 5 is a perspective view of two tubes superposed and flattened outwith air centering devices alternating therewith.

FIG. 1 illustrates a cylindrical casing 10* through which air is passedin the direction of the casing axis to extract heat from fluid such asmolten metal circulated within a toroidal heat exchanger tube assemblygenerally indicated at 12 and located within the casing. V

The heat exchanger assembly .12 comprises 30 groups of tubes, oneintegrated group being shown in FIG. 2. Ten of these groups are locatedin each of three planes transverse to the axis of the casing 10. In eachgroup of tubes are placed ten individual tubes 14 such as illustratedand then reverse its direction of flow for discharge from the outlet 20.Inter-posed between these plate-like tubes 14 are air centeringdevices'22 such as are commonly used in radiators and the like forconveying heat to or from air guided by such devices.

In FIG. 2, ten of the tubes 14, with the requisite number of air centers22, are constrained to an involute form within a side plate 24. Thelatter includes two flanged end portions 26 and 28 and an intermediatearcuate por-- tion 30. The thirty intermediate portions 30 define acentral zone coaxial with said casing. The marginal edge 31 (FIG. 4) ofeach involute plate tube 14 opposite the inlets and outlets 18 and 20 iscaused to approach but not contact the arcuate or intermediate portion30 of the-side plate 24. This provides a clearance A for expansion andcontraction purposes between the tubes and the portion 30 extending bythe ends-of the tubes, as will be obvious. The side plates 24 ofadjacent groups of tubes 14 are in interfacial contact as clearly shownin FIG. 3.'

The inlets 18 of the ten tubes 14 of a given group are connected to acommon arcuate inlet tube 32 which extends almost, but not quite, thedistance between the flange plates 26 and 28. The clearance B (FIG. 3)at the ends of this tube 32 permits expansion and contraction.

' An arcuate tube 34 parallel with a-corresponding tube 32 is likewiseprovided for each group of ten tubes 14, but, in this case, it isadapted to serve as a discharge tube for that particular group, theoutlets 20 being connected thereto. A short inlet neck 36 communicateswith each arcuate tube 32 and a short outlet neck 38 communicates witheach'ar'cuate outlet tube 34. The necks 36and 38 areoffsetinsofar astheir radial positions are concerned with respect to the axis of theexchanger or its casing 10.

It will be noted in FIG. 3 that the flanged endportion welding orotherwise.

in FIG. 4. Each tube 14, when flattened out, is in the roll bonded andplate form, being expanded from a flat piece by known methods such asshown, for example, in the United States Patent 2,662,273 grantedDecember 15, 1953, in the name of G. R. Long and entitled Method ofMaking Heat Exchange Structures. It will be noted that each tube 14 isso formed as to provide eight passages 16, four of which directlycommunicate with an inlet tube 18 made integral with one end of the tubestructure. The other four passages 16 communicate directly with an exittube 20. The inlet and exit are at one end of the flat supply for themolten metal.

The diameter of the casing 10 is adequate to permit installation of aC-formation intake manifold tube 40. FIG. 3 illustrates how thismanifold tube clears the casing 10 as well as the main bodies of theflat tubes 14.

Extending in the direction of the axis of the casing 10 are ten paralleland tapered intake manifolds 42. Each of these serves to connect theC-shaped manifold 40 with the intake neck 36 of each of three groups oftubes. In other words, the main manifold 40 serves asan inlet manifoldfor thirty groups of tubes or three hundred tubes 14. It will be notedin FIG. 3 that the main manifold 40 is such that the latter clears theexterior periphery of the air centering devices 22 and the exteriorbroadends of the tubes 14.

, At the other end of the cylinder 10 or adjacent to the other endthereof is located a main discharge manifold 44 similar to the intakemanifold 40 and provided with tapered discharge manifolds 46 each ofwhich is connected to the necks 38 of the three groups of tubes.

An extension 47 of the intake manifold 40 passes through an opening 48of the casing 10' to a source of A bellows type expansion joint 50 sealsthe space between the casing and the extension 47 and another extension52 also passes through the casing 10 and a seal is provided by a secondbellows type structure 54.

Molten metal enters at 47 and passes from the main intake manifold 40 tothe thirty groups of tubes 14 by way of the tapered manifolds 42,arcuate tubes 32 and tube inlets 18. This fluid passes through the tubes14 giving up its heat to the air which passes in the axial direction ofthe casing =10. The cooled molten metal then is discharged from thetubes 14 by way of the outlets 20 to the arcuate tubes 34 and thenenters the discharge manifold 40 by way of the tapered manifolds 46.Final discharge is by way of the extension 52.

It will be noted that the sole support for the tubes 14, the aircentering devices 22 and the manifolding is by way of the side plates 24as joined to the interior cylindrical wall of the casing 10. Theinvolute shape of the plate or flat tubes 14 and the clearances A, B andothers provided permit expansion and contraction without undue stressesand strains being imposed. It should also be noted that the involutetubes define air passages of uniform thickness giving a uniform heatdistribution to the components of the exchanger. This eliminates hotspots and contributes to more eificient performance by the heatexchanger.

We claim:

1. A heat exchanger comprising a cylindrical casing with a givenaxis anddefining a flow passage for one fluid, groups of flat tubes and fluidcentering devices arranged in toroidal form within said casing and inaplane perpendicular to said axis, the said flat tubes and centeringdevices of each group being arranged alternately, each of said tubes andcentering devices being in involute form and extending outwardly towardthe periphery of said casing, each of said groups being separatelyencompassed by side plate means, the opposite ends of said side platemeans being fixed to said casing, an intermediate portion of said sideplate means extending by the ends of the corresponding tubes and beingout of contact with said tubes and centering devices, the intermediatevportions of the side plate means of said groups cooperating in defininga zone centrally within said casing, each said flat tubes having a flowpassage for a second fluid and'having an inlet 2. A heat exchangercomprising a casing forming a conduit for one fluid, groups of flatSided tubes and fluid groupsbeing separately encompassed by side platemeans having flat surfaces extending parallel with the flat sides ofsaid tubes, opposite ends of said side plate means being fixed to saidcasing, an intermediateportion of said side plate means partial-1ydefining said central zone, said centering devices being arranged toguide said one fluid into intimate contact with said tubes, said flattubes being out of contact with said side plate means permittingexpansion and contraction of the latter independent of the tubes, eachof said flat tubes having an inlet and an outlet for a second fluidlocated near the inside wall surface of said casing, and inlet andoutlet manifolding connected to the inlets and outlets of all the groupsof tubes.

3. A heat'exchanger as set forth in claim 2 in which the side platemeans of each one of said groups is in interfacial contact with the sideplate means of the adjacent groups, and the inlet and outlet manifoldingsubstantially encircles the said groups and comprises ducts locatedbetween said groups and the said inside wall surface of said casing.

2,195,259 Ramsaur Mar. 26, 1940 2,655,181 Cooper Oct. 13, 1953 2,656,157Wasielewski Oct. 20, 1953 2,869,834 Clark et al Jan. 20, 1959 FOREIGNPATENTS 173,859 Switzerland Mar. 16, 1935 791,051

Great Britain Feb. 19, 1958

